Halfmile’s Pacific Crest Trail maps are the most current and accurate Pacific Crest Trail maps available and widely used by thru-hikers and section hikers. Halfmile and many other volunteers have spent months with a GPS logging the trail and marking PCT landmarks from 2007 – 2014.

What’s so great about Halfmile’s PCT maps?

Based on all new GPS data from 2014. These are the most current and accurate PCT maps available.

We noticed recently that Ruffwork’s popular PCTHYOH app is no longer available from the Apple iTunes app store. The app was widely used by Pacific Crest Trail hikers to store Halfmile maps for offline viewing when cellular or wi-fi internet connections are not available.

2) Launch the Safari app on your iphone and navigate to http://www.pctmap.net/maps-url-loading/ The .pdf map files on this web page are optimized for viewing on smartphones and are not compressed .zip files that would require a special app to uncompress them.

3) Select a link to a map section and the map will load into Safari. You can view Halfmile maps in Safari, but only when you have a cellular or wi-fi internet connection.

Using Safari to view a Halfmile .pdf file in another iphone app. Note the “Open in…” option that appears after tapping the map.

4) Tap the map in Safari app and note the “Open in…” option.

Apps available to open .pdf files will vary depending on what apps are installed on your iphone.

5) When you select “Open in…” you will find the option to open the Halfmile .pdf map with any iPhone apps that support .pdf files. Select “Open in Adobe Reader.”

Viewing a Halfmile Map in Adobe Reader.

6) The Halfmile .pdf map will be opened in Adobe Reader and stored for offline viewing.

7) Repeat the steps for each map section you want to download to your smartphone.

A library of Halfmile Maps available for offline viewing from the Adobe Reader Documents menu.

8) You can see all the stored .pdf files in the Adobe Reader Documents menu option.

It’s best to load maps in Adobe Reader when you have a wi-fi internet connection or a strong LTE cellular signal.

Adobe Reader is a very useful app for hikers that will store and view any .pdf file such as Halfmile Maps, the PCT Water Report (use the links to .pdf format not .html format), bus schedules, instructions manuals, and many other documents.

Halfmile PCT apps are a companion to Halfmile’s 2015 printed map set to aid navigation. The app determines your location and, if on the PCT or one of its side trails, it calculates trail distances to over 3,000 PCT landmarks and displays any relevant trail notes. The app also calculates elevation gains and losses to landmarks and compass bearings and distance to landmarks. The IOS app includes a live trail diagram to aid navigation.

Halfmile apps do not contain maps of the Pacific Crest Trail — think of them as a very accurate, location aware, digital PCT Data Book.

Changes for 2015 include:

The app data is now synchronized with the official 2015 Halfmile maps and GPS data.

Over 1000 new PCT landmarks have been added for locations such as water sources, trail junctions, campsites, road crossings, etc.

Over 90% of the PCT track data has been replaced using much higher accuracy sources than before.

Compatibility with new smartphones and new operating systems.

Various small fixes and enhancements have been made to improve readability.

The new elevation profiles feature color coding in the style of FAA Aeronautical Charts, improved formatting to show more waypoints, and mileage that matches the 2015 Halfmile PCT mileage estimates.

Information on the elevation profiles includes:

Page numbers to identify which PCT map pages are covered.

Black dots for every half mile of trail.

Red dots marking individual waypoints along the PCT.

PCT mileage from the Mexican border every two miles.

Elevation gain/loss is estimated (see the red circle above) for every two mile section of PCT.

The new elevation profiles are included with each section of PCT maps, or just the new elevation profiles for California can be downloaded here, or Oregon/Washington profiles can be downloaded here. Since PCT mileage estimates have changed for 2015, be sure not to mix and match 2014 and 2015 version of PCT maps, apps, or GPS data.

We have been asked by several hikers about the abbreviations used for waypoint names on Halfmile Project PCT maps, apps, GPS data, and Google Earth files. Here is a list of the most common abbreviations:

The 2015 Pacific Crest Trail hiking season is rapidly approaching and understandably we have been getting questions about what’s changing in the 2015 edition of Halfmile’s PCT maps and when new maps, apps and GPS data will be ready.

GPS reception can be challenging along some parts of the PCT due to tree cover or terrain such as mountains or canyons that sometimes block GPS signals. This is especially true in Oregon and Washington. The custom GPS logging hardware performed amazingly well because of the outstanding performance of the ublox NEO-7P GPS module, external mast mounted antennas, and the merging of multiple GPS data sets using software developed by David Lippke. We are confidant this is the most accurate data ever collected of the PCT.

Overall the new 2015 data has an average horizontal accuracy of 1.9 meters. Here is the horizontal accuracy by PCT section:

Both apps are designed to be a companion to Halfmile’s Pacific Crest Trail printed map set to aid navigation on the PCT. The app determines your location and, if on the PCT or one of its side trails, it calculates trail distances to 1,700 PCT landmarks and presents any trail notes relevant for the location.

Features of both apps include:

Simulation mode for hike planning and hiker support

Provides specific “how to walk there” instructions for all points

Live trail diagram with optional compass orientation

Calculates cumulative elevation gains and losses to all points

Powerful search function for features like water sources, campsites, and resupply locations

Pacific Crest Trail hikers are often interested in knowing the elevation gained or lost as they hike along the Pacific Crest Trail. The 2014 Halfmile Project estimates the total elevation gain/lost for a northbound thru-hiker is 489,418 feet of climbing and 488,411 feet descending with an overall change of 1,007 feet as they hike from Campo to Manning Park.

Here is a breakdown of elevation gain/loss by PCT section:

Gain

Loss

Change

CA_Sec_A

16,452

-16,335

117

CA_Sec_B

19,006

-20,698

-1,692

CA_Sec_C

22,427

-20,775

1,652

CA_Sec_D

26,944

-27,403

-459

CA_Sec_E

21,200

-19,894

1,306

CA_Sec_F

14,891

-13,469

1,422

CA_Sec_G

23,576

-18,061

5,515

CA_Sec_H

32,804

-34,987

-2,183

CA_Sec_I

14,320

-13,257

1,063

CA_Sec_J

14,049

-16,282

-2,233

CA_Sec_K

10,661

-10,887

-226

CA_Sec_L

5,282

-7,893

-2,612

CA_Sec_M

18,095

-20,421

-2,326

CA_Sec_N

17,106

-16,424

682

CA_Sec_O

17,961

-18,747

-785

CA_Sec_P

19,147

-15,326

3,821

CA_Sec_Q

9,311

-13,918

-4,608

CA_Sec_R

14,290

-11,390

2,900

OR_Sec_B

8,124

-7,427

697

OR_Sec_C

9,008

-8,056

951

OR_Sec_D

7,588

-8,422

-834

OR_Sec_E

9,614

-9,394

220

OR_Sec_F

15,476

-16,619

-1,144

OR_Sec_G

8,965

-12,924

-3,958

WA_Sec_H

29,552

-25,348

4,204

WA_Sec_I

18,327

-19,744

-1,417

WA_Sec_J

18,773

-17,711

1,062

WA_Sec_K

31,441

-30,641

799

WA_Sec_L

15,030

-15,958

-928

Total

489,418

488,411

1,007

It turns out that estimating elevation gain/loss is a surprisingly complex and technical process. The Halfmile Project has put a great deal of effort into this, and our estimates are much more accurate than, say, the ones that Google Earth produces, or any other source of PCT information.

Elevation values obtained from GPS units are much too noisy for use in gain/loss calculations — even from the survey grade equipment that we now are using on the Halfmile Project. Instead, elevation data is based on USGS 1/3 arc second DEM (Digital Elevation Model) data.

Halfmile Project gain/loss estimates use approximately 3/4 million GPS sample points along the Pacific Crest Trail. The elevation for each sample points is calculated based on a grid of 525 USGS 1/3 arc second DEM rectangles that surround the point. A two dimensional spline interpolation is then generated using the DEM rectangles to calculate the exact elevation of each sample point.

Blue lines are the elevation spline plots calculated based on 525 USGS DEM elevation rectangles. The center of each DEM rectangle is marked with a black dot. The elevation of a GPS sample point is then calculated, in this example as 1,252.04 meters. The process is repeated about 3/4 million times.

Observant (or obsessed) readers may have noticed that the Halfmile Project elevation estimates changed slightly from 2013 to 2014. This year’s total elevation gain of 489,418 feet is slightly less than the 492,871 foot estimate last year. The reason for the changes are:

The DEM data itself is constantly being updated and improved by the USGS.

In some sections of the PCT we completely replaced the data with more accurate GPS data.

In all sections we changed our selection of points (i.e., doing a bit smarter job this year).

Last year’s interpolation was from a grid of 36 surrounding points and this year 525 grid points were used.

While these changes are very small, even small changes add up over thousands of points.

One reason we put so much effort into elevation calculations, is so that the elevation gain/loss estimates match between the printed maps and smart phone apps. The Halfmile smartphone apps calculate very accurate elevation gain/loss estimates between your current on-trail location and any landmark along the trail.

The Halfmile smartphone app estimates an elevation gain of 7,102 feet and a loss of 4,047 feet along the Pacific Crest Trail from the Southern Terminus to the water fountain near the Burn Rancheria Campground.

If you want even more details about Halfmile Project elevation estimates, David Lippke AKA White Jeep posted a detailed summary recently on the PCT-L. Here is a copy of what he posted:

Hi, Lon alerted me regarding the PCT elevation gain/loss stats conversation here and so I thought some direct information might help. I’m the author and maintainer of the Halfmile apps and I generated all the elevation data and gain/loss numbers published for the last three annual cycles. I spend most of my time working on improving both the horizontal and vertical accuracy of all our PCT data. This effort has ballooned over the last couple years involving more than just myself and Halfmile with the deployment of survey grade equipment to the trail, custom GPS logging devices, and now further generations of all that we are scrambling to deploy for the 2014 season.

Anyway, people often wonder how we calculate elevation gain and loss numbers along the PCT. It turns out that this is a surprisingly complex and technical process. The net is that we currently generate profiles that are much more accurate than, say, the ones that Google Earth produces. That said, there is still substantial room for improvement and we are working on that.

The technical TLDR is that our point elevation values are produced by heavily processing USGS DEM 1/3 arc second data. Our gain / loss calculations then operate over this set using a smoothing factor consistent with the average error present in the DEM data and the average horizontal “side to side” path jitter observed along side slopes.

Most will want to stop reading here. 100% tech talk follows. You have been warned.

Going on in more detail, the process does not involve using GPS elevation data at all. As noted by Brick, elevation values obtained from GPS units are much too noisy for use in gain and loss calculations — even from the survey grade equipment that we now use. Instead, our raw source for elevation data is the USGS 1/3 arc second DEM (Digital Elevation Model) which provides average elevation values over rectangles that are approximately 8×10 meters on a side (the “8” varies with latitude).

We start with our best filtered GPS horizontal data for each bit of trail. This ranges in horizontal accuracy from 1/2 meter (California sections L through O) to 3-5 meter accuracy (e.g., WA J) to unknown accuracy data that we hand select from the competing data sets. Over 2014 for the 2015 update, we hope to bring the average horizontal accuracy for the entire PCT to the vicinity of a single meter.

Then we translate all those horizontal points to the horizontal datum used by the USGS and we fetch the DEM elevation values needed generate a grid of 525 points surrounding each subject point. Using those 525 points, we generate a two dimensional spline interpolation and query it at the exact point. This process is repeated for all 3/4 million horizontal data points and involves almost 11 million unique 1/3 arc second DEM values.

So at this point in the process we have the best possible estimate for the elevation of each track point and way point expressed in terms of the NAVD88 vertical datum (quasi MSL) with the primary error sources being that of the USGS DEM (RMSE ~2.5 meters) and that of our collected horizontal positions.

In the next step, we reduce the horizontal point count so that all sections stay within Garmin’s 10K track point limit. We do this by applying the Ramer-Douglas-Peucker algorithm with a 1.9 meter sigma overall and, in more accurate sections, a 1.25 meter sigma. In other words, when the trail is going along a straight road or the aquaduct, the points can be several hundred meters apart but in tight turns they may only be a couple meters apart.

Finally, to calculate gains and losses between points, a tally is kept from track point to track point except that no gain or loss is recorded until a track point is reached that has an elevation loss or gain more than 5 meters from the starting track point. When that occurs, the algorithm moves forward to the current end track point and picks up the counting again. When reporting the gain / loss to a particular way point, any residual in the smoothing is closed out so that the numbers all “add up”. As a side note, this creates a small numerical issue when one decides to total our published per-section numbers over the whole trail and compare those to the whole trail numbers in the (soon to be released) 2014 version of the Halfmile apps — our per-section numbers are “closed out” with respect to this 5 meter smoothing but the app just keeps rolling through the boundaries.

Sorry for the tech talk, but I just wanted to address all the speculation about what feeds into these calculations. Questions are always welcome and so is project involvement — we have all manner of “task” available for the inclined.

CA Section O
Survey grade GPS data collected for this section (sub-meter accuracy)
Improved mileage estimates based on more accurate GPS data
New half mile waypoints created based on more accurate GPS data
Renamed RD1425 to RD1424B
Renamed RD1453 to RD1452
Renamed WA1468 to WA1467
Renamed WA1469 to WA1468
Removed waypoints from GPS data that were not on any map

WA Section J
New GPS data collected for this section (five new tracks merged for greatly improved accuracy)
Improved mileage estimates based on more accurate GPS data
New half mile waypoints created based on more accurate GPS data
Added note that the Chevron Station may not accept packages
Renamed WACS2445 to WACS2446
Renamed WA2455 to WA2456
Corrected description of Goldmyer Alternate (mile 11.4), where you do not cross the bridge but continue on E side of river